Multi-zone drilling system with spiral drills and quick adjustment for flat and deep drillings at a minimum jutting-out length of the drill attachment

摘要

The multi-zone drilling system consists of a spiral drill provided, over its whole length, with continuous spiral slots and a uniform core diameter, which drill is driven by steel clamps mounted in the bottom portion of the drill chuck and engaging the spiral slot surfaces. The spiral drill is furthermore provided, at its upper end, with an annular slot pin, extractably fixed in an annular slot-locking sleeve; this annular slot-locking sleeve is in turn mounted in a pressure element which is vertically adjustable in a delicately stepped way via a connecting bush, for the purpose of altering the jutting-out length of the drill attachment in the drill chuck.